The Hornets, once again, lacked any of the belief, aggression or cohesion required as the Baggies enjoyed what must have been one of their most comfortable home matches in some time.
A sparse away end became sparser when the third goal went in, several travelling supporters hitting the road early as their side showed little idea of how to get back into it.
Isaac Price had swept in an opener in the first half, before Daryl Dike nodded in a second from a set-piece before the break.
Giorgi Chakvetadze in possession (Image: Alan Cozzi/Watford FC)
Ed Still’s side briefly rallied after half-time but created little, before their hosts re-established dominance and ran out comfortable winners, Danny Imray firing in a third with over 20 minutes to play.
The Hornets slip to 15th in the Championship, having taken two points from their last six games in an end to the season that calls into question deep-rooted mentality and culture issues at the club.
West Brom notionally had the better of the opening exchanges, though Egil Selvik comfortably saved their only efforts inside the first 10 minutes from Isaac Price and Josh Maja.
The Baggies continued to dominate, though, and took a deserved lead when Imray’s low cross evaded a couple of defenders and was converted by Price.
Watford nearly levelled immediately with their first serious attempt, Papy Mendy’s ferocious 20-yard volley stopped by Max O’Leary in the hosts’ goal.
Jeremy Petris in possession (Image: Alan Cozzi/Watford FC)
Watford caused a couple more moments of worry from set-pieces but were still chasing the ball in the main, Alex Mowatt drilling wide from the angle of the box.
Three minutes before half-time, it was two.
Price’s free-kick lobbed up off Nestory Irankunda’s arm and found Daryl Dike unmarked to flick in at the near post, another ugly set-piece goal conceded to add to the collection in recent weeks.
The Hornets went in two goals down at half-time having lacked any of the necessary belief and aggression to give themselves a chance.
Imran Louza, dropped from the starting XI, was introduced at half-time for Irankunda as Still sought a way back into the game.
Othmane Maamma comes forward (Image: Alan Cozzi/Watford FC)
The Hornets did dominate territory from there but never looked particularly like creating, Luca Kjerrumgaard heading straight at O’Leary in the nearest miss before the hour mark.
Kwadwo Baah and Jeremy Ngakia were introduced but it made little difference – and the visitors were soon three down.
Price was unmarked at the back post and headed the ball back to Josh Maja, who sliced his effort – but Imray was on hand to smash in a third.
The game played out in sorry fashion from there, the inevitable having long been established.
The number of basic technical errors was remarkable, James Abankwah letting the ball slip under his foot in the latest of several mistakes but going unpunished as Selvik saved from Aune Heggebo.
Watford sunk without a trace as this dreadful season finale continued, Othmane Maamma slicing one effort wide and bobbling a late volley at O’Leary.
Two more games to go before the club must tackle several serious problems this summer.
Watford XI: Selvik; Petris (Ngakia 63), Pollock, Abankwah, Keben; P. Mendy, Kayembe; Irankunda (Louza 46), Chakvetadze (Baah 63), Maamma; Kjerrumgaard (Doumbia 75)
Unused subs: Baxter, Bola, Bove, Ince, Nabizada